Hubble s constant the oosterhoff dichotomy and hydrogen ionization fronts
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Hubble’s Constant, the Oosterhoff Dichotomy and Hydrogen Ionization Fronts. Shashi M. Kanbur University of Florida, September 2009. Acknowledgments. Chow Choong Ngeow, Douglas Leonard, Lucas Macri, Robert Szabo, Robert Buchler, Marcella Marconi.

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Hubble s constant the oosterhoff dichotomy and hydrogen ionization fronts

Hubble’s Constant, the Oosterhoff Dichotomy and Hydrogen Ionization Fronts.

Shashi M. Kanbur

University of Florida,

September 2009


Acknowledgments
Acknowledgments Ionization Fronts.

  • Chow Choong Ngeow, Douglas Leonard, Lucas Macri, Robert Szabo, Robert Buchler, Marcella Marconi.

  • SUNY Oswego undergrads: Dylan Wallace, Dan Crain, Greg Feiden, Richard Stevens, Robin Dienhoffer, Frank Ripple, Sean Scott, Earl Bellinger, Lillie Ghobrial, Mike Evans, Martin Berke.

  • Isaac Richter, Tim De Haas, Andy Missert, Matthew Turner, Alex James, Eamonn Moyer, Jillian Neeley.

  • NSF, AAS, HST.


The cepheid pl relation
The Cepheid PL Relation Ionization Fronts.

  • This relation is not linear – at least in the LMC: change of slope between short (log P < 1) and long (log P > 1) period Cepheids.

  • OGLE II/III data using OGLE determined reddenings and the Zaritsky reddening map.

  • Need detailed statistical tests for this.

  • It is NOT sufficient just to look at the slopes plus or minus some standard deviations.


Multiphase pl pc relations
Multiphase PL/PC relations Ionization Fronts.

  • http://www.oswego.edu/~kanbur/IRES2009/Vphase.mov

  • http://www.oswego.edu/~kanbur/IRES2009/Iphase.mov

  • http://www.oswego.edu/~kanbur/IRES2009/Cphase.mov

  • http://www.oswego.edu/~kanbur/IRES2009/Wphase.mov


Lmc tests
LMC tests Ionization Fronts.

  • F test.

  • Schwarz Information Criterion.

  • Testimator plus others.

  • OGLE II/OGLE III plus long period Cepheids.

  • MACHO, Sebo et al, Perrson et al.

  • OGLE II reddenings plus Zaritsky reddenings.

  • BVIJH non-linear.

  • K marginally nonlinear. OGLE II Wessenheit linear, OGLE III Wessenheit marginally nonlinear.

  • PL/PC cancel each other out – that is the Wessenheit is linear.


Jhk data
JHK Data Ionization Fronts.

  • 3 years observing campaign using 1.5m NOAO telescope plus CPAPIR and OGLE LMC pointings.

  • 2 years of Sloan filter data again using LMC OGLE pointings.

  • Analyzing this data currently.


M33 direct data
M33 DIRECT data Ionization Fronts.


Impact on h0
Impact on H0 Ionization Fronts.

  • Calibrate SNIa diagram with Cepheids.

  • μ0 = μV – 2.45(μV – μI).

  • W = V – 2.45(V-I).

  • There is a difference when used with OGLE III with these data.

  • W is less sensitive to possible changes of slope in V and I.

  • http://www.oswego.edu/~kanbur/IRES2009/H0impact.pdf


Mid infrared pl relations
Mid-InfraRed PL relations Ionization Fronts.


Physics
Physics Ionization Fronts.

  • PL/PC relation connected through the PLC relation.

  • PC relation affected through the interaction of the stellar photosphere and hydrogen ionization front (HIF).

  • Engaged: Color of star which is related to the Temperature of photosphere = temperature of HIF.

  • Engaged at low densities: Color of Star is related to temperature of photosphere which is less dependent on period.

  • Engaged at high densities: more sensitive to period.

  • Sudden: - either engaged or not.

  • ML relation affects phase/period of interaction.

  • Flat PC relation at maximum light for Galactic Cepheids, and for logP > 1 for LMC Cepheids.


Pc ac relations
PC/AC Relations Ionization Fronts.

  • Lmax ~ R2max T4max, Lmin ~ R2min T4min

  • Amplitude ~ 4log(Tmax – Tmin).

  • PC relation flat at maximum light – AC relation at minimum light and vice versa.

  • See this in LMC OGLE II/III Cepheids.

  • http://www.astro.umass.edu/~shashi/papers/paper1.pdf


Rr lyraes
RR Lyraes Ionization Fronts.

  • PC relation at minimum light is flat.

  • Higher amplitude RR Lyraes are driven to hotter/bluer temperatures/colors at maximum light.

  • PC relation is flat at minimum light because the HIF is further out in the mass distribution.

  • HIF always engaged with stellar photosphere for RR Lyraes.

  • But density changes as pulsation proceeds from minimum light.

  • http://www.astro.umass.edu/~shashi/papers/paper9.pdf


The oosterhoff dichotomy
The Oosterhoff Dichotomy Ionization Fronts.

  • OoI: <P> ~ 0.65 days, Z = 0.001

  • OoII: <P> ~ 0.55 days, Z = 0.0001

  • Period-Amplitude (PA) relation different in the two groups.

  • Evolved RRab stars in OoI clusters follow a similar PA relation to that in OoII clusters

  • M3: OoI, M15: OoII.

  • V = a + blog P

  • V = a + c(B-V) – c(B-V) + blogP

  • Related to PC/AC relations as a function of phase


M3 m15 analysis
M3/M15 analysis Ionization Fronts.

  • M3 data from Benko et al (2007)

  • M15 data from Corwin et al (2008)

  • Fourier decomposition to smooth out observed data.

  • Use decomposition to estimate max/min.

  • BVI light curves.

  • Concentrate on RRab stars.

  • Possible evidence of a difference in PC/AC relations as a function of phase.


Pc ac relations in rr lyraes
PC/AC relations in RR Lyraes Ionization Fronts.

  • Sloan RR Lyraes and M31 data usign HST.

  • Theoretical models computed by Robert Szabo.

  • M,L,T,X,Z. Two values of Z=0.001, Z=0.0001

  • Range of M/L. Strong possibilities to constrain models and estimate reddening.

  • Kurucz atmosphere parametrized by effective gravity and photospheric temperature.

  • Comparing models with observations and understanding possible implications.


Model results
Model Results Ionization Fronts.


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